Authorization has already been completed - 
Cause:
This error typically happens when the funds for this order have already been captured via the PayPal portal. Due to the funds already being captured PayPal is unable to capture the funds a 2nd time when the Order Manager
has requested PayPal to capture the funds.
Recommended Resolution:
Please confirm that the funds have been captured via the PayPal System. Once confirmed please process the order and we can assist in removing the order from the Order Manager Open/Pending Queue.